Friday, July 15, 2011

The history of modern electronic communications begun with Alexander Graham Bells telephone experiments, where speech was able to be converted into electrical energy, transmitted along physical wires and reconstructed at the receiver. Speech, which is actually vibration of the air, vibrated a paper cone to which a small coil was attached. This induced an electrical signal into the coil, which was proportional to the vibration of the paper cone. Alexander Graham Bell, born in Edinburgh, Scotland, 1847, emigrated to the United States, settling in Boston. Bell, interested in the education of deaf people, invented the microphone, and later, in 1876, an electrical speech machine, called the telephone.

By 1878, Bell set up the first telephone exchange in New Haven, Connecticut, and in 1884, long distance connections were made between Boston, Massachusetts and New York City.

In these early experiments at transmitting speech. copper wire was used as the connection media over which the signals traveled. This is due to copper wire being a very good conductor, which lets electrical signals flow down the wire easily.
As the telephone became popular, more and more people wanted to communicate with each other, so a switching center (telephone exchange) evolved. Each customer was connected to the telephone exchange via a pair of wires, which carried the signal from their telephone.